Table I.

Ferric chelate reductase activities (nmol Fe reduced g⁻¹ fresh wt min⁻¹ and flavin concentrations (nmol g⁻¹ fresh wt) in root tips from Fe-sufficient and -deficient sugar beet

	+Fe (0–10 mm)	−Fe		−Fe YZ/+Fe	−Fe WZ/+Fe
		YZ	WZ
FC-R activity	13 ± 2	138 ± 5	39 ± 5	11	3
Riboflavin 3′-sulfate	4 ± 1	406 ± 79	91 ± 30	102	23
Riboflavin 5′-sulfate	2 ± 1	98 ± 12	30 ± 4	49	15
FAD	10 ± 2	67 ± 3	49 ± 9	7	5
Riboflavin	n.d.	13 ± 2	6 ± 1	–	–

Data are means ± se of five replicates. n.d., Not detected.